#48 Jörg: automated single user mode into AppleJack at startup?

[Kristofer Widholm]

I do remote administration on Macs by ssh. It would be
great if there was an option "reboot the machine. Do an
"applejack BIGBANG reboot". Leave a logfile. I relogin
10 minutes later and look at the log.
I would not dare the remove VM files on a running
machne remotely. :-)

Thanks a lot,
Jörg

[Kristofer Widholm]

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Implementing this would necessitate modifying the startup
sequence of Mac OS X. If you know of a safe way to do this,
please post it here. As it is, this scares me, much as I
would love to be able to do this. But I don't know how to
enter single user mode programmatically on reboot. I only
know you have to hold the cmd+s key down.

Again, if you know of a safe, easily reproducible and
reversible way to hard-code "startup in single user mode
next time, but only once" into the Mac boot sequence, I
would love to know it.

[Nobody/Anonymous]

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I would like to second this request. The ability to reboot
a remote machine and run an applejack auto reboot would be
phenomenal.

[Nobody/Anonymous]

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If its possible to set the machine to boot into single user
mode after every reboot with something like nvram
boot-args="-s" couldn't you then automate the running of
Applejack and finish and reset nvram boot-args=" "? The
question is how can you make applejack autolaunch once
single-user mode has started?

[Kristofer Widholm]

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These are interesting suggestions, and I would like to be
able to do it. Starting applejack up automatically is not a
problem, as it could require just a temporary modification
of the /var/root/.profile which gets loaded when the single
user mode z shell gets loaded.

However, modifying the nvram on a remote machine would need
to be industrially tested, and I am only a solitary
developer with three computers available for testing.

In addition, if something goes wrong I would end up spending
all my time trying to offer support. I already spend at
least 8 to 10 hours a week interacting with AppleJack users,
and I don't have any more time or resources to devote to it.

If a company wanted to offer AppleJack support, I think
rolling in this feature would be interesting. I just think
the potential fallout of bugs and the like is quite enormous.

The other thing to point out is that if you really want to
run a non-interactive series of tasks on remote Macs, you
can just write a shell script to do what you want. All the
interactive stuff in AppleJack is just unnecessary overhead
from a sysadmin's perspective, so why not just write a shell
script that would reboot into itself, clear all caches
everywhere (if that's what you want), reset the nvram again,
and reboot a second time?

[Kristofer Widholm]

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Another thing to consider is what to do about Macs with
locked-down nvram settings? This is very common in IT dept
rollouts of Mac OS X.

[Nobody/Anonymous]

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This is exactly what I was wishing for as well. I hope you can figure out how to safely run "applejack AUTO restart" on a remote machine.

[Kristofer Widholm]

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I would love to be able to add this feature, but I am wondering a few things. How is the remote machine connected? SSH? Remote Desktop?

Also, I would like to avoid having to load networking in single user mode since doing so could make AppleJack unusable if its the networking that is causing the computer's problems in the first place.

Maybe one of you can post some example scripts of how you currently run commands on remote machines?

Thanks.